1. Field of the Invention
The present invention relates to a communication device, a communication and a method therefor with which plural users are enabled to commonly use storage means on a network with keeping securities.
2. Description of the Related Art
There has been hitherto known a network storage in which plural users located at geographically different places are connected to one another through the Internet to enable file data communications (reception and transmission) among them.
In the conventional network storage, a storage environment is given to every individual user, and thus users can never use the storage environments of the other users. Furthermore, services which are available to other users can be supplied to the other users by authenticating the other users with open ID and password for the other users concerned or teaching URL (address) of file data which are wished to be commonly used.
For example when plural users commonly use a storage on a network as a memory by using computers connected to the network concerned, it is required to manage access authority every user. However, as described above, if the access management to the storage is carried out by using IDs and passwords, for example, it would be impossible to perform access management with which directories in a storage and file data stored in the directories concerned are diversely defined. Furthermore, with the method using URL as described above, an access to the storage by an unjust user is unavoidable and thus the securities cannot be kept.
The term “just” as used herein means authenticated or authorized, and the term “unjust” means not authenticated or not authorized, as the case or context permits. The term “justice-judged” means “judged to be authorized,” and the term “unjust-judged” means “judged to not be authorized,” as the case or context permits. For example, the phrase “justice-judged users” refers to those users who were judged to be authorized to access a given resource, and the term “unjust user” refers to an unauthorized user.